1. Field of the Invention
The invention relates to a transcutaneous implantation catheter. Besides providing access to blood vessels and other cavities in the human body, the present invention is also applicable in the field of peritoneal dialysis.
2. Description of Related Art
A continuous ambulant peritoneal dialysis (CAPD) requires peritoneal catheters that lead through the abdominal wall of a patient and are enclosed therein by tissue. A peritoneal catheter is known from German periodical "Der Chirurg" (1983), pages 609-612, which consists of a continuous hose comprising three sections. Between a intraperitoneal first section and a second section intended to be encapsulated by tissue in the abdominal wall, there are retaining elements in the form of a sleeve for delimiting the abdominal wall section of the hose, a Dacron disc and a silastic ball for fixing the catheter to the lamina posterior of the rectus sheath. Between the second section and the extracorporal third section, there is a Dacron sleeve for anchoring in the subcutis. This known peritoneal catheter generally consists of a silicone hose. The second section, destined to be set into the tissue of the muscle or the skin, causes the growing of a smooth enclosing tissue sheathing in the implantation tunnel in the tissue between the points of concretion formed by the sleeve and the disc, the tissue sheathing not adhering to the catheter. Liquid gathers in the gap between the catheter and the enclosing sheathing, which can easily be infected. Moreover, it has been found out that this area is continuously subjected to a strong reaction between fibroblasts, macrophages and skin cells due to the use of Dacron sleeves in the area of the skin, where the tissue grows around the catheter. This reaction often leads to inflammations.
Further, percutaneous means of access are known that grow together with the body tissue and form a location of access for a catheter to be inserted. Such a means of access is described in European Patent Application 0 164 896 (Thermedics). The catheter used in connection with the means of access also has a smooth exterior so that the body tissue in the implantation tunnel forms a tunnel sheathing enclosing the catheter.
German patent 28 06 030 and U.S. Pat. No. 4,588,461 describe vascular prostheses consisting of a porous hose made of a non-woven fiber fabric of fine polyurethane fibers. Body tissue will grow onto such vascular prostheses. Vascular prostheses replace blood vessels or other vessels in the body that had to be removed, for example, because of thrombosis. Accordingly, vascular prostheses are set into the body of a patient completely. The means of access described in European Patent Application 0 164 896 has two non-woven layers of polyurethane fibers with different porosity that are to allow the growing in of epithelium cells and collagen producing fibroblasts at defined locations in subcutaneous implantation. The non-woven layer with the smaller pore width is disposed on the surface of the "neck" of the means of access and should have a fiber spacing of 75-100 .mu.m. It is oriented towards the skin and is meant to allow the growing in of epithelium cells. In contrast thereto, the disc-shaped part of the means of access, which is arranged in the subcutaneous range, is defined by a fiber spacing between 400 and 800 .mu.m and is intended to allow the ingression of fibroblasts which will afterwards from collagen fibers.
It is an object of the present invention to provide a transcutaneous implantation catheter wherein the risk of defensive reactions and infections in the implantation tunnel is reduced. It is a further object of the present invention to provide a transcutaneous implantation catheter in which the cells intended to grow into the catheter shall dispose of the necessary space between the fibers even if the catheter has not been implanted by a surgeon with perfect accuracy, but has been positioned only approximately at the precise location, for example, by means of the stylet technique.